Molecular detection and genetic characterisation of pathogenic Theileria, Anaplasma and Ehrlichia species among apparently healthy sheep in central and western Kenya
2019
Ringo, Aaron E.(Obihiro University of Agriculture and Veterinary Medicine National Research Center for Protozoan Diseases) | Aboge, Gabriel O.(University of Nairobi Faculty of Veterinary Medicine Department of Public Health, Pharmacology and Toxicology) | Moumouni, Paul F. Adjou(Obihiro University of Agriculture and Veterinary Medicine National Research Center for Protozoan Diseases) | Lee, Seung Hun(Obihiro University of Agriculture and Veterinary Medicine National Research Center for Protozoan Diseases) | Jirapattharasate, Charoonluk(Mahidol University Faculty of Veterinary Science Department of Pre-clinic and Applied Animal Science) | Liu, Mingming(Obihiro University of Agriculture and Veterinary Medicine National Research Center for Protozoan Diseases) | Gao, Yang(Obihiro University of Agriculture and Veterinary Medicine National Research Center for Protozoan Diseases) | Guo, Huanping(Obihiro University of Agriculture and Veterinary Medicine National Research Center for Protozoan Diseases) | Zheng, Weiqing(Nanchang Center for Disease Control and Prevention Department of Disinfection and Vector Control) | Efstratiou, Artemis(Obihiro University of Agriculture and Veterinary Medicine National Research Center for Protozoan Diseases) | Galon, Eloiza M.(Obihiro University of Agriculture and Veterinary Medicine National Research Center for Protozoan Diseases) | Li, Jixu(Obihiro University of Agriculture and Veterinary Medicine National Research Center for Protozoan Diseases) | Thekisoe, Oriel(North-West University Unit for Environmental Sciences and Management) | Inoue, Noboru(Obihiro University of Agriculture and Veterinary Medicine) | Suzuki, Hiroshi(Obihiro University of Agriculture and Veterinary Medicine National Research Center for Protozoan Diseases) | Xuan, Xuenan(Obihiro University of Agriculture and Veterinary Medicine National Research Center for Protozoan Diseases)
Tick-borne diseases (TBDs) caused by Theileria, Babesia, Anaplasma and Ehrlichia species are common in tropical and subtropical regions. In this study, we investigated the presence and genetic diversity of Theileria spp., Anaplasma ovis, B. ovis, E. ruminantium and Anaplasma spp. in sheep from the Machakos and Homa Bay counties of Kenya. In order to improve the diagnosis and control of ovine TBDs, a total of 76 blood samples from apparently healthy sheep were screened using a polymerase chain reaction (PCR). The assays were conducted using primers based on Theileria spp. 18S rRNA, Anaplasma ovis Major surface protein-4 (AoMSP4), B. ovis 18S rRNA, E. ruminantium pCS20 and Anaplasma spp. 16S rRNA. The overall infection rates for Theileria spp., A. ovis, E. ruminantium and Anaplasma spp. were 39/76 (51.3%), 26/76 (34.2%), 6/76 (7.9%) and 31/76 (40.8%), respectively. The overall co-infection was 47/76 (61.8%). All Theileria spp. positive samples were confirmed to be of Theileria ovis on sequencing. A phylogenetic analysis of the 18S rRNA gene sequences of T. ovis revealed that all isolates of this study clustered with T. ovis sequences extracted from the GenBank suggesting this gene is highly conserved. E. ruminantium pCS20 sequences were in the same clade on the phylogenetic tree. However, three AoMSP4 sequences from this study appeared in the same clade, while one sequence formed a separate branch revealing genetic divergence. The 16S rRNA sequencing revealed uncharacterised Anaplasma spp. and A. ovis. The phylogenetic analyses of the uncharacterised Anaplasma spp. revealed that the two sequences from this study appear in an independent clade from other sequences extracted from the GenBank. This study provides important information regarding the occurrence of tick-borne pathogens and their degree of genetic diversity among sheep in Kenya, which is useful for the diagnosis and control of TBDs.
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